Epsilon Update No. 7: SHX

The next monthly update about Epsilon — a solo adventure game about exploring a dark and corrupting forest. The SHX challenge system.

As the launch of Exclusion Zone Botanist: Epsilon approaches, I’ll be posting regular updates with a behind-the-scenes look at the design decisions going into the game:

• Epsilon Update 01: Epsilon overview and launch dates

• Epsilon Update 02: Plant features

• Epsilon Update 03: Plant morphology

• Epsilon Update 04: Exclusion Zone map

• Epsilon Update 05: Character creation

• Epsilon Update 06: Playtesting

Note that everything here is in development and subject to change. These updates are a snapshot of how things looked when they were written.

Follow the Kickstarter pre-launch page to be notified when it goes live!

Discoveries that impact game state

From the beginning, I wanted the things you discovered in the EZ to have an impact on the game state. That was hard to fit into the original one-page, trifold version of Exclusion Zone Botanist that was released in 2022.

I was able to add a touch of it in the expanded zine version, particularly in Plant Group D.

For example, the toxic fog (D1) plant feature causes your coughing, vomiting, and the agent blindly running through the forest. This is implemented by marking that hex on the map and then rolling to immediately move to a random adjacent hex. That hex becomes a permanent hazard, preventing easy backtracking. The random movement messes with your plans.

The time loop (D3) and dyschronometria (D4) change the normal game loop and time progression — either slowing it down or skipping ahead. The lashing vines (D6) force a die roll to attempt to dodge them. Failing the roll results in immediately applying the next effect from the corruption list.

I think these added a lot to Exclusion Zone Botanist, and players seemed to agree. In fact, most wanted more. That’s where Epsilon’s challenge system comes in.

Creating a challenge system

Pushing your luck is the core concept of Exclusion Zone Botanist and is also at the core of Epsilon. This is present in the pressure to get as far as possible into the EZ, knowing that every step farther in is another step that will need to be taken on the way back out too. I always want the decision of when to turn back to be a difficult one.

So when it came time to implement a challenge system, that feeling of pressure and risk needed to be present.

Some inspiration came in the form of Ahoy designed by Greg Loring-Albright and published by Leder games. In the pirate-themed game, players must load their cannons before firing at another ship.

They do this by slotting a six-sided die into a specific spot on their player board. Then, when they attack, they can choose to “turn down” that die — spending pips to add to their attack roll.¹ What makes this so interesting is that you need to turn down the die before your opponent makes their opposing roll.

It creates a tough decision: How much do I spend of this limited resource? How badly do I want to win this specific battle? Do I need to save for future encounters?

Of course, that’s not enough for a roleplaying game core resolution system. I knew I wanted to include character creation and skills that would impact the chance of success. I wanted bloom (formerly corruption) to be part of the equation. At the same time, I certainly didn’t want a complicated multi-stat, multi-step system.

Thus was born the SHX system.

The SHX system

The system I came up with over the last year or so uses just three stats or factors: Stamina, Health, and one other (X). The X can be rethemed as necessary for the setting.² That’s why I’m calling it the SHX system.

Here’s how SHX works in Exclusion Zone Botanist: Epsilon:

1. Tracker dice: The player uses 3 six-sided dice to track the three values in Epsilon: Stamina (S), Health (H), and Bloom (X). These are not rolled. They are simply used for tracking. All three individual values must always be in the range of 1-6, as indicated by the six-sided dice.

2. Bloom as temporary cap: The Bloom acts as a cap or temporary maximum for the other two values. The sum of [ Stamina + Health ] must always be less than or equal to [ Bloom + 7]. At the start of the game, Bloom is 1. That means the total (sum) of Stamina + Health must be less than or equal to 8.

3. Stamina (S): Stamina can be spent to increase the chance of success for challenges, but may never be reduced less than 1 or increased higher than 6.³

4. Health (H): If Health is ever reduced to less than 1, the game ends in failure.

5. Bloom (X): If Bloom is ever increased higher than 6, the game ends in failure.

Using this system, when Bloom is low, you are safe from ending the game by acquiring too much corruption and mutation. It also means, however, that your Stamina and Health are limited.

Being mutated by the forest isn’t a good thing, and yet it increases your Bloom, which allows you to have a higher Stamina and/or Health. So maybe it’s not a bad thing?

For example, when your Bloom is at 5, the sum of your Stamina + Health could go as high as 12 (5+7). That would allow you to max out both individual Stamina and Health values at 6.

Thematically, Bloom doesn’t just mutate and degrade your body. In some ways, it invigorates you. It makes you stronger.

Of course, this change comes at a cost — a lethal one if taken too far.⁴

Resolving a challenge with SHX

Challenges in Epsilon happen where there is a chance of success or failure. Some are optional and others are mandatory.

Every turn in Epsilon, you either (a) discover a new plant, or (b) have an encounter in the EZ. Challenges are attached to both encounters and some plant features. So there is always a chance of a challenge.

For example, the encounter might involve a clearing full of little brown mushrooms. In a single puff, they all erupt, ejecting their spores into the air. The brown cloud is everywhere. You would then resolve a challenge to determine if you successfully avoided the impact of the spore cloud or not.

Challenges work by rolling dice versus a target number known as a Challenge Rating (CR).⁵ Most challenges are CR 9 but others might be easier or harder.⁶ Each challenge has an associated skill type (e.g. Wilderness, Threat, Precision, or Exertion).

Here’s the process to resolve a challenge:

1. Push past limits: Optionally convert Health into Stamina at a ratio of 1:1. This is overexerting yourself to get a short term boost at a cost. Health is generally difficult to recover. Limits on maximum Stamina and Health still apply.

2. Bid stamina: Optionally spend Stamina to gain a bonus to the challenge roll. Each pip turned down will increase the roll by 1. Stamina may never be turned down less than 1. The most Stamina that can ever be added to a single challenge roll is 5.

3. Roll the dice: Roll 2d6 for the challenge. Add the Stamina bonus to the sum of the dice rolled.

4. Equipment bonus: Add +1 to the result if using a single applicable equipment item that would significantly increase the chance of success.

5. Skill bonus: Add or subtract 1 based on the character’s background skills such as Wilderness, Threat, or Precision. Each challenge has a designated skill type.

6. Compare results: Compare the final result versus the CR:

   1. Result ≥ CR = Success

   2. Result < CR = Failure

Each challenge has an associated Success/Failure result that can then be read and applied.⁷ Most have mechanical impacts on the player or game state.

In the spore cloud example above, success means you stumble back and your lungs burn, but you are ultimately able to hold your breath and get away. Failure means you trip, fall, and despite your best efforts you inhale some of the spores. Your Health increases, but you also immediately check for an increase in Bloom.

How you choose to spend your Stamina, what items you acquire, and your character’s background all impact your chance of success while in the EZ.

Nothing new (but sort of new)

There are other systems that use 2d6 dice, that have three stats, or that have resources that can be spent to increase dice rolls.⁸

That said, the SHX system is distinctive enough that I gave it a name:

• Two stats (S+H) that are bound by a third stat (X).

• The X stat only ever increases and never decreases, resulting in failure if it goes too high. This means you want it to increase a little but not too much.

• Stamina can be spent to improve rolls but only as a bid prior to the roll.

• The resources can be converted, but only in certain directions. Health can be converted to Stamina, but Stamina can never be converted to Health.⁹

• Skills, equipment, and other factors can be easily implemented as +1/-1 modifiers while keeping the math relatively simple.

• The same system can be used for combat rolls with full or partial success.

• The system can be rethemed to fit other settings. I have a dungeon crawl game in the works that uses Stamina, Health, and Terror as the three stats.¹⁰ If it continues to work as well as I’d expect, you’ll see this in a lot more Exeunt Press games in the future.

The SHX system received nothing but kind words during the recent Unpub playtest. In fact, players considered challenges and this system to be some of the strongest parts of the game.

So I feel good about including it in Epsilon and really hope you enjoy it!

Follow the Epsilon project

I am posting an Epsilon update on the third Friday of every month through development, launch, and fulfillment. You can read previous updates in the Exeunt Omnes archive.

What do you think? Does the SHX system sound good to you? If you are familiar with similar TTRP core resolution systems, please share them in the comments. I’m particularly interested in ones that allow bidding prior to rolling and/or the spending of resources to boost a result.

- E.P. 💀

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1. In this context “turning down” a die is just decreasing the value of it. To turn down a die from 6 to 5, you would simply turn the die so instead of having the 6 pip side being face up, the 5 pip side would be facing up and visible.

2. SHX is intended to be flexible but not universal. It would not work for every game and every setting. It is particularly suited for push-you-luck horror such as zonecore.

3. While Stamina is usually physical stamina, it can also include mental stamina. So it’s more of a general combination of both physical and mental stamina.

4. While the actual mechanisms are quite different, this is absolutely inspired by the Sanity Track in Cthulhu: Death May Die (Daviau & Lang, 2019).

5. I know that Challenge Rating (CR) has a different meaning in Dungeons & Dragons, but I prefer using the term anyway. It’s not final and subject to change.

6. A CR 9 has a 27.8% chance of success if no stamina is bid and no other bonuses are applied. If you had a +1 in a relevant skill, that would increase your chance of success to 41.7%. Bidding 1 Stamina would increase that to 58.3%. The steps in probability are intentional. I like that spending Stamina makes success very likely, and yet it is a limited resource. Some tasks aren’t worth the cost to succeed.

7. The system would easily support partial success or partial failure results, particularly on a tie with CR. I’m just not convinced that adding that into Epsilon is the right move.

8. While I’m not intimately familiar with the systems, I think both Blades in the Dark and Ironsworn have ways to spend a resource to improve rolls. Nobilis doesn’t use dice at all and instead allows players to spend a resource. Feel free to provide more examples and/or correct me in the comments if I’m wrong.

9. In a multiplayer fantasy setting, it could be interesting to allow a magic user to drain the stamina of the others in their party to restore their own health.

10. I can imagine what the social internet would call this system if it had the abbreviation SHT instead of SHX.